The eastern portion of Ecuador in the Amazon Basin (the "Oriente") comprises
the lowlands that gradually slope downward from 600 m to less than 200 m at the eastern
frontier with Peru (Balslev and Renner 1989; Tschopp 1953). The topography is low and
undulating to slightly hilly terrain between broad swampy floodplains of the main rivers.
Geologically the Oriente is part of the extensive area filled with Cretaceous-Tertiary
sediments between the Andes and the Brazilian Shield (Tschopp 1953).

This region is drained by the Napo and Pastaza river systems, which diverge
respectively toward the north-east to east and the south-east from the depression between
the Andean uplifts of the Serranía del Napo (with Sumaco Volcano) and the Sierra de
Cutucú (Tschopp 1953). The Napo is the major river, flowing eastward to join the
Marañón River near Iquitos, Peru (CPD Site SA9) and form the
Solimões River, which in turn flows eastward to Manaus, Brazil (CPD
Site SA5).

Yasuní National Park covers 9820 km² south of the Napo River and north of the Curaray
River in Napo and Pastaza provinces of central eastern Ecuador, extending eastward from c.
40 km east of the town of Coca (76°40'W) almost to Nuevo Rocafuerte near the border with
Peru (Map 44). Much of the park's northern boundary is the
Tiputini River and much of the southern boundary is the Curaray River. There is a roughly
rectangular north-western extension of the park to the south bank of the Napo River at
Añangu and westward to the Indillama River.

The adjacent Waorani Ethnic Reserve includes 6100 km². The eastern part of the reserve
is largely encompassed to the north, east and south by the park. The reserve extends
westward to c. 77°30'W, but is almost bisected by the Auca road which runs south from the
town of Coca (or Puerto Francisco de Orellana), an oil centre and port. A broad swath of
land 10 km wide on either side of the road is occupied by colonists, but more or less
south of the road a corridor provides the Waorani Amerindians access between the eastern
and western portions of their reserve.

Most of the park and reserve has low hills of red clay dystropept soil. Low humic gley
soil probably occurs in the swampy or poorly drained areas in the eastern part of the park
(Duellman 1978; Neill 1988b). There are no peat swamps or podzols (Balslev and Renner
1989).

Weather stations some distance west and east of the park suggest that the annual
temperature averages 25°C (with extremes of 15° and 38°) and the annual rainfall is
2425-3145 mm, with a humidity of 88%. Although rarely rainless for more than c. 10 days,
between August and February some months may be drier (Balslev et al. 1987; Blandin
Landívar 1976; Duellman 1978). Flooding is not seasonal (Balslev and Renner 1989).

The entire region is within the tropical moist-forest life zone of the Holdridge
system. The park and reserve are in the Solimões-Amazonas phytogeographic region (Nations
1988). Four main vegetation types have been recognized within the park and reserve, but
the vegetation has not been mapped.

1. Probably more than 90% of the area is unflooded upland
("tierra-firme") forest, occurring on the low hills of red clay
dystropept soil. The canopy is 25-30 m high, with emergents such as Cedrelinga
cateniformis (to 45-50 m tall and 2-3 m dbh) and Parkia spp. Canopy trees
include several Myristicaceae (Otoba glycycarpa, Osteophloeum platyspermum, Virola
spp.). Simaruba amara, Dussia tessmannii, Hymenaea oblongifolia and
several genera of Moraceae and Sapotaceae also occur. Trees with buttresses or stilt roots
are frequent. The understorey on hills may be quite open with small trees and shrubs,
lianas may be abundant, and epiphytes are less diverse and abundant than in wetter forest
nearer the Andes (Neill 1988b). The ground layer tends to be only weakly developed
(Balslev et al. 1987).

2. Along the banks of the Napo River is a narrow strip (200-1000 m wide) of relatively
fertile soil, enriched by sediments from the Andes when the river floods. This "várzea"
forest is generally flooded only once every several years. The canopy layer is
somewhat higher (35-40 m) than in the upland forest, with occasional emergents such as Ceiba
pentandra and Ficus spp. to 50 m tall. Common canopy dominants include Otoba
parvifolia, Chimarrhis glabriflora, Celtis schippii and Guarea
kunthiana. The ivory-nut palm Phytelephas macrocarpa is a common small
understorey tree.

3. The third type of vegetation is swamp forest, which occurs in
extensive stands along the Napo River and the lower reaches of the Tiputini River, a main
tributary of the Napo. Swamp forest is flooded for much of the year, but the ground is
exposed during dry periods. Characteristic are nearly pure stands of the palm Mauritia
flexuosa, as well as a few other swamp species such as Virola surinamensis and Symphonia
globulifera.

4. The Yasuní River is a black-water river, which bears very little sediment because
its headwaters are in the Amazon lowlands rather than the Andes. The waters are stained
the colour of dark tea by tannic acids dissolved from riverside vegetation. Along the
banks of this river and associated lagoons is "igapó" forest,
which is almost totally floristically distinct from the upland and várzea forests. Common
trees include Macrolobium acaciifolium, Coussapoa trinervia and the palm Astrocaryum
jauari.

The Napo River region of Ecuador and Peru has been proposed as one of the primary
Pleistocene forest refugia, characterized by a high degree of animal and plant endemism.
The refugium extends from the foothills of the Andes eastwards to the "Trapecio
Amazónico" of Colombia and Peru (Duellman 1978; Prance 1982) - the park and reserve
are within a more finely delimited South Napo Pleistocene refugium.

The upper part of the Amazon Basin may have emerged from a mid-continental lake and
become forested as recently as 1.8 million years ago, with the greatest uplift of the
Andes. During climatic fluctuations of the Pleistocene and Holocene the forest may have
become fragmented, and then rejoined north and south but been separated by drier areas to
the east (e.g. Duellman 1978). For the Oriente as a whole, which however is just a part of
the postulated Pleistocene refugium, Balslev and Renner (1989) estimated endemism at only
1%. The plant species composition of the park and reserve remain unknown, as does the
extent of regional endemism represented within them.

The little collecting and study done so far at one area (Añangu) showed high but not
exceptional richness for moist lowland forest (Balslev and Renner 1989). Some 394 species
of trees over 10 cm dbh were found: 153-228 species per ha in unflooded forest and 146 in
floodplain forest, with 19% shared. As usual in the neotropical lowlands, Moraceae and
Leguminosae were most frequent. So little known is the region that in two weeks of field
work near an exploratory oil well in the western part of the park, several new species of
trees and at least two new orchid species were discovered, as well as over 15 records of
orchids new for Ecuador (Neill 1988b). The flora of the region contains many species in
common with the lowlands of the nearby Gran Sumaco and Upper Napo River region (see Gran
Sumaco Data Sheet, CPD Site SA38), but the distribution of the
flora in Amazonian Ecuador is highly heterogeneous - many species present in the wetter
Gran Sumaco region do not occur in the Yasuní region, and vice versa.

In late 1992, botanists from the National Herbarium of Ecuador and the Missouri
Botanical Garden initiated a large-scale floristic inventory along the oil-pipeline road
which is being built through 120 km of primary forest in the Yasuní National Park and
Waorani Ethnic Reserve. Specimens were collected from felled trees. This survey has
continued for two years and will provide much more thorough knowledge of the flora.

Little that is definitive can be said until the flora is better known. Hevea
guianensis is present - a less commercially desirable rubber tree than H.
brasiliensis, but an important genetic resource. Phytelephas macrocarpa (the
vegetable-ivory palm) also is found - a species that has received renewed international
commercial interest. Cedrelinga cateniformis, which is prized for construction of
dugout canoes, has potential as a commercial timber. This species might replace the
dwindling Spanish cedar (Cedrela odorata) and bigleaf mahogany (Swietenia
macrophylla), which are among the valuable timber trees selectively taken from
accessible areas along the rivers.

The two protected areas are embraced by the large Napo and Upper Amazon lowlands
Endemic Bird Area (EBA B19), which extends from southernmost Colombia and eastern Ecuador
eastward into northern Peru and westernmost Brazil. Ten species of birds are limited to
this area, although they essentially represent the most restricted species of a
(distributionally poorly known) suite of birds that are confined to the river islands,
riverine forest and várzea forest of the Amazon Basin rivers. The birds in this EBA, just
one of which is considered threatened, are seemingly confined to the tierra-firme or
várzea forests.

The Waorani Ethnic Reserve protects tribal land of the Waorani ("Auca")
Amerindians, some of whom have fiercely resisted all outside efforts to contact them
(Nations 1988; Whitten 1981; Yost 1981). Oil exploration began in their area in the 1940s.
The Waorani ethnobotany is notably different from that of neighbouring peoples, suggesting
their past isolation. Several family groups of Waorani live in the eastern portion of
Yasuní park.

In 1992, a large-scale conservation programme known as SUBIR (Sustainable Use of
Biological Resources) was initiated for the Yasuní region as well as two other protected
areas in Ecuador. The goals of SUBIR are to promote conservation by increasing the
capacity of Ecuadorian agencies to protect core areas, as well as encouraging
non-destructive uses of natural resources by peoples living in buffer zones around the
protected areas. Financed by the U.S. Agency for International Development, SUBIR is
carried out by a consortium of organizations led by CARE International, with the
collaboration of the Ecuadorian Ministerio de Agricultura y Ganadería (Ministry of
Agriculture and Livestock) and local environmental and community organizations.

The SUBIR programme seeks to help develop viable economic alternatives that will enable
people in the buffer zones to produce sufficient income without causing deforestation or
other resource-destructive activities. These alternatives may include ecotourism,
production of handicrafts and other goods from the forest, and improved agricultural
techniques that obviate the need to continually clear more forested land. SUBIR is an
experiment in its initial stages; its results will not be evident for several years.

The forests of Ecuador's Oriente are undergoing extensive deforestation as a result of
oil exploration and production followed by colonization, which began with the most recent
and successful phase of exploration in 1964-1969 (Schodt 1987). These activities led to
the construction of a 420-km oil pipeline to transport petroleum from the Oriente oil
fields over a 4300-m high pass in the Andes and down to the port of Esmeraldas on the
Pacific coast. With the pipeline, the first roads were constructed into Ecuador's
north-eastern Amazon and then south, in 1971 opening the region to colonization, e.g.
through relocation of farmers from the over-crowded coastal and mountain regions of the
country (Bromley 1973; Neill 1988a). Where a few thousand lived 20 years ago, now over
100,000 people live in Napo Province and are transforming large tracts of forest into
agricultural fields and pastures (Uquillas 1984). African oil palm (Elaeis guineensis)
is the favourite plantation crop. Selective logging occurs where the trees are accessible.

In the mid 1980s, new oil fields were located in the Pastaza and Napo river valleys,
including a significant reserve of 150 million barrels of heavy crude petroleum beneath
the Waorani Ethnic Reserve and Yasuní National Park. Ecuador's plan for extraction by
building a road as well as a pipeline to the oil fields through the untouched Yasuní
forest, instead of flying in materials, sparked intense controversy within Ecuador as well
as internationally. The government's PetroEcuador awarded a concession for development of
the oil reserves in petroleum block 16, which occupies 2000 km² within the Waorani
reserve, to the U.S.-based company Maxus. In December 1992, construction of the road and
pipeline began from the Napo River south into the centre of the Waorani reserve-Yasuní
park territory, amid continuing opposition from Ecuadorian environmental organizations.

The environmental mitigation plan for the development project within the
Yasuní-Waorani area includes some provisions for reducing negative impacts. Strict
control of persons entering the road is planned to avoid settlers and logging, and wells
are to be drilled in clusters to reduce deforestation. However, the feasibility of being
able to prevent invasion of the park and reserve by colonists once the road is established
is questionable. The events that often follow the building of a road in a protected area
are sadly recorded nearby. Construction of oil-pipeline roads through the Cuyabeno
Wildlife Reserve north of the Napo River led to colonization of the area by more than 1000
families.

The discovery of oil in the Oriente has brought considerable prosperity to Ecuador (oil
exports provide 70% of the country's income) (Schodt 1987), greatly increased
opportunities for colonization in the region and emphasized the need to protect its
diverse biological resources - which also are of economic significance. Two large reserves
were created in 1979: Cuyabeno Wildlife Reserve (2547 km²) north of the Napo River and
Yasuní National Park (originally 6797 km²) - the largest mainland park in Ecuador.

Due in part to the conflict between conservation of protected areas and development of
oil fields, the size and shape of Yasuní park have been changed twice by governmental
decrees. An ethnic reserve of 1600 km² for the Waorani was established in 1968,
south-west of the original Yasuní park boundary (Whitten 1981). Until the 1960s, the
Waorani were nomadic over c. 20,000 km² (nearly all of the territory between the Napo and
Curaray rivers) and their hostile reactions to all outsiders had kept their land nearly
undisturbed (e.g. Kvist and Holm-Nielsen 1987).

In 1990, the Waorani Ethnic Reserve was enlarged eastward to 6100 km², and a large
part of Yasuní park was ceded to the Waorani reserve, including the major portion of the
oil fields near the Yasuní River. As partial recompense for loss of the park lands,
additional territory was added on the south-east of Yasuní NP. In 1992, the park was
enlarged again to 9820 km². Together with the Waorani reserve, the officially protected
Yasuní region now comprises almost 16,000 km².

An important step toward the legal protection of the region was the May 1989
declaration of the park and its buffer zone as a Biosphere Reserve, under UNESCO's Man and
the Biosphere Programme (Coello Hinojosa and Nations 1989). The Biosphere Reserve now
includes the Waorani Ethnic Reserve and the enlarged Yasuní NP. However, the future of
the park and reserve remain uncertain. The oil reserves will last only 20 years. Over the
long term it will be more productive to protect the genetic resources of the region and
promote tourism that can generate steady income. Future generations of Ecuadorians
especially could have the legacy of a great Amazonian park, the homeland of indigenous
people, and an extraordinary representation of plant and animal species in one of the
world's diverse large wilderness regions.

A preliminary master plan for the park has been prepared by the Departamento de
Administración de Areas Naturales y Vida Silvestre of the Ministerio de Agricultura y
Ganadería (Coello Hinojosa and Nations 1989). However, the changing boundaries of the
park, the establishment of the Waorani Ethnic Reserve and the petroleum development
necessitate thorough revision of the management plan for the region. Legal mechanisms for
future management and environmental protection of the Waorani Ethnic Reserve, in
particular, have not been clarified by the government. The conservation outlook for the
Yasuní region is not yet bleak - the Maxus petroleum company which holds the development
concession in the area has demonstrated a commitment to support conservation efforts.

Among other contributions, Maxus agreed to build a scientific research station within
the park, which is to be managed by the Pontificia Universidad Católica del Ecuador,
Quito. The first major research project of the station is studying the forest dynamics of
a diverse 50-ha permanent plot established on the Tiputini River (Foster 1994).

Whitten Jr., N.E. (1981). Amazonia today at the base of the Andes: an
ethnic interface in ecological, social and ideological perspectives. In Whitten Jr., N.E.
(ed.), Cultural transformations and ethnicity in modern Ecuador. University of
Illinois Press, Urbana. Pp. 121-161.

Yost, J.A. (1981). Twenty years of contact: the mechanisms of change
in Wao ("Auca") culture. In Whitten Jr., N.E. (ed.), Cultural transformations
and ethnicity in modern Ecuador. University of Illinois Press, Urbana. Pp. 677-704.